simjian



F 1956 L. G. SIMJIAN 2,735,232

POLISHING DEVICE Original Filed May 22, 1953 FIG. I FIG. 2 2 SUPPLY l4 IO l4 ZT f I2 Em 'II i l3 FIG. 3 1

FIG.6

3 SUPPLY F'G. 5 AND swn'cu LUTHER G. SIMJIAN INVENTOR ATTORNEY United States Patent POLISHING DEVICE Luther G. Simjian, Greenwich, Conn ass'ignor to The Reflectone Corporation, Stamford, (101111., a corporation of Connecticut Original application May 22, 1953, Serial No. 356,742. Divided and this application April 11, 1955, Serial N0.50.0,344

-6 Claims. (Cl. 51-7) This invention is .a continuation-impart of my application, Serial No. 356,742, filed May 22, 1953, and relates to a polishing device for polishing or surface abrading irregular articles. It has particular reference to a polishing bath which contains magnetic particles, the viscosity of which is modified by the application of a magnetic field.

As used throughout the specification and claimsthe word surrounding shall not be construed as limiting to complete surrounding, but include also partial and incomplete surrounding of the object surface to be polished.

One of the major difficulties in polishing irregular articles lies in the necessity for applying an abrasive material to the irregular contour. For this reason many irregular articles must be polished by hand without the use of the usual motor operated hurling or a brading wheels. The present invention solves these difliculties by using an abrasive or polishing bath for polishing irregular objects, employing a mixture which consists of an abrasive powder such as 'Carborundum, a magnetic powder such as iron filings, and a liquid which may be any type of lubricating oil. This mixture is housed in a container in which the object to be polished is placed. An alternating magnetic field is applied to the mixture in such a manner as to magnetize it and cause the particles to move in small circular or spiral paths. A two or threephase magnetic field is necessary to produce this motion.

One of the objects of this invention is to provide a polishing device which avoids one or more of the disadvantages and limitations of prior art arrangements.

Another object of the invention is to polish an irregular object without resorting to manual manipulation.

Another object of the invention is to abrade the surface of an irregular object for the removal of scale, dirt, and paint.

One feature of the invention includes a container which holds a magnetic abrasive mixture. The object to be polished is immersed in the mixture and an alternating polyphase magnetic field is applied to the mixture. Another feature includes the use of two or more magnetic field patterns with means for switching from one pattern to another during the polishing operation.

For a better understanding of the present invention together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

Fig. 1 is a side view of the polishing device showing some parts in section.

Fig. 2 is a plan view of the polishing device shown in Fig. 1.

Fig. 3 is a polishing device similar to Fig. 2 but using a three-phase supply instead of a two-phase.

Fig. 4 is a cross sectional view of a polishing device similar to that shown in Fig. 3 but having a double set of three-phase electromagnets.

Fig. 5 is a cross sectional view showing a polishing device in which the object to be polished is rotated by outside means.

Fig. 6 is a schematic wiring diagram showing how con- .nections should be made to the electromagnets in the device shown in Fig. 4.

Referring now to ,Figs. 1 and 2, a non-magnetic container 10 is employed for retaining a mixture 11 which includes magnetic particles, abrasive particles, and a liquid. A magnetic core 12 is arranged so that its pole pieces 13 project to a position adjacent to'the walls of the container. Suitable magnetic windings 14 are placed on the pole pieces and induce an alternating magnetic flux in the pole pieces and in the mixture to provide the abrasive action. The four "windings 14 are connected to a two-phase supply 15 which first produces .a magnetic flux in any two opposed pole pieces, thereby tending to produce magnetic lines of force in the mixture which have a general direction in parallel to a diameter. A short time interval later, magnetic flux is induced between the other two opposed pole pieces and create magnetic lines of force which are in general at right angles to the first induced lines of flux. The continued application of the two-phase current supply produces a rotating magnetic field in the container which is similar to the rotating magnetic afield produced in the armature of a two-phase motor. This rotating magnetic ,field acts on the magnetic particles in the mixture and causes them to turn in small circles, -the diameter of which depends upon the viscosity of the liquid, the strength of the magnetic field, .and the frequency of the alternating current supply. The magnetic particles carry with them abrasive particles in the mixture and cause the polishing or abrading action.

It will be evident that an irregular surface may be polished by using time abrasive materials such as finely powdered aluminum oxide or rouge. If an .ab-rading action is desired, course particles may be used such as emery .or Carborundum.

The device shown in Fig. 3 is similar to that shown in Fig. 2 except that a three-phase supply 16 is employed and only three pole pieces 17 are necessary. The action is the same, a rotating magnetic field is established by current through windings 18 and the magnetic particles in mixture 11 are given a circular motion as before.

The devices shown in Figs. 1, 2, and 3 are suitable for flat circular objects such as discs and gears. If it is desired to polish or abrade thicker articles the arrangement shown in Fig. 4 is employed. This device includes the usual container 10 and mixture 11 but employs two or more magnetic systems. The first of these includes a core 20 having three windings 21 (only two shown in Fig. 4). A second core 22, similar to core 20, is mounted adjacent to the bottom of container 10 and includes three windings 23. The pole pieces of core 22 are displaced from the pole pieces of core 20 by an angle of 30 mechanical degrees, thereby providing an additional mixing action when both these magnetic systems are in operation. The wiring arrangement forsuch a multiple system is shown in Fig. 6 and comprises a three-phase supply 24 which includes a switching arrangement which periodically switches from windings 21 to windings 23 and back again. This switching means may be a relay operated device or a commutator mechanism run by a motor. At one interval of time, coils 23 are connected together with supply lines 25. After a few cycles, the switching device switches the current to lines 26 and windings 23. The three-phase magnetic flux from either one of the sets of windings produces a circular motion of the iron filings within the mixture.

The arrangement shown in Fig. 5 comprises a support for an object 30 held within the mixture 11 in container 10, such support including a shaft 21 to which is secured a pulley 32 mounted on a hinged arm 33. Pulley 32 is turned by a flexible belt 34 which passes over a multiple pulley 35 and is run by motor 36. The mag netic field pattern may be either two or three-phase or some other convenient polyphase arrangement, indicated in Fig. by pole pieces 37 and 38 and energized by winding 40. When the object 30 is turned within bath 11 the polishing action is made more uniform and dead spots are avoided.

From the above description it will be evident that a polishing mixture comprising magnetic particles, abrasive particles, and a liquid can be employed in conjunction with a polyphase magnetic field to polish metal surfaces and to provide an efficient cleaning and abrasive action.

While there have been described and illustrated specific examples of the polishing device it will be obvious that various changes and modifications may be made therein without departing from the field of the invention which should be limited only by the scope of the appended claims.

I claim: I

l. A polishing device comprising; a mixture in a container which surrounds an object to be polished; said mixture comprising a liquid, abrasive particles, and magnetic particles, and means for applying a polyphase alternating magnetic field to the mixture for alternately varying the viscosity of the mixture and for displacing the particles in the mixture.

2. A polishing device comprising; a mixture in a container which surrounds an object to be polished; said mixture comprising a liquid, abrasive particles, and mag netic particles; and electromagnet means for applying a polyphase alternating magnetic field to the mixture and causing a displacement of the magnetic particles, said electromagnetic means including a polyphase alternating current applied to a plurality of windings on a magnetic core.

3. A polishing device comprising; a mixture in a container which surrounds an object to be polished; said mixture comprising a liquid, abrasive particles, and magnetic particles; and electromagnetic means for applying a polyphase alternating magnetic field to the mixture and causing a displacement of the magnetic particles; said means including a plurality of pole pieces mounted adjacent to said container, a plurality of windings on the pole pieces, and a polyphase alternating current applied to the windings.

4. A polishing device comprising; a mixture in a container; said mixture including a liquid, abrasive particles, and magnetic particles; a support for holding an object to be polished in said mixture; and means for applying a polyphase alternating magnetic field to the mixture; said means including a polyphase alternating current applied to a plurality of windings on a magnetic core adjacent to said container.

5. A polishing device comprising; a mixture in a container which surrounds an object to be polished; said mixture comprising a liquid, abrasive particles, and magnetic particles; and electromagnetic means for applying two polyphase alternating magnetic fields to the mixture for causing a displacement of the magnetic particles, said electromagnetic means including a first set of pole pieces mounted adjacent to the container with means for producing an alternating magnetic flux between said pole pieces and a second set of pole pieces also mounted adjacent to said container with additional means for producing an alternating magnetic flux between said second set.

6. A polishing device comprising; a mixture in a container; said mixture including a liquid, abrasive particles, and magnetic particles; a support for holding and rotating an object to be polished in said mixture; and means for applying a, polyphase alternating magnetic field to the mixture; said means including a polyphase alternating current applied to a plurality of windings on a magnetic core adjacent to said container.

References Cited in the file of this patent UNITED STATES PATENTS 

